The present invention relates generally to a composition of matter that exhibits a synergistic biological effect containing homo-oligonucleotides of 5-fluoro-2xe2x80x2-deoxyuridine-5xe2x80x2-O-monophosphate (FdUMP) and 5-fluorouracil (5-FU). In another aspect, the present invention relates to combination therapy exhibiting a synergistic anti-proliferative effect on cancer cells when compared to the activity of the individual compounds of this invention. The compositions of this invention are of use in the treatment of cancer in animals, including humans.
Anti-metabolite nucleosides and nucleoside analogs have found widespread use in the treatment of cancer and other human diseases. One such nucleoside analog, 5-fluorouracil (5-FU) has been used continuously since its development in 1957 by Duusinski and Heidelberger (U.S. Pat. No. 2,802,005) for the treatment of solid tumors of the head and neck, breast, and colon. 5-FU was originally designed to work as an inhibitor of thymidylate synthetase (TS), the enzyme which converts deoxyuridine 5xe2x80x2-O-monophosphate (dUMP) to deoxythymidine 5xe2x80x2-O-monophosphate (dTMP). It is believed that 5-FU retards tumor expansion by causing thymidine pools to become depleted in rapidly proliferating tumor cells.
Protocols for the administration of 5-FU for treatment of human cancer involve infusion of the drug for long periods of time. 5-FU is rapidly metabolized and excreted with a half-life in-vivo of about 18 minutes. While 5-FU is an effective anti-cancer agent when metabolically activated to become an inhibitor of TS or incorporated into nucleic acids, its effectiveness is hampered by rapid metabolism and formation of 2-fluoro-xcex2-alanine (FBAL) which is neurotoxic and cardiotoxic. For these reasons researchers and clinicians have long desired a method of increasing the therapeutic index and target specificity of 5-FU.
A variety of pro-drug forms of 5-FU have been developed to address the issues of cellular uptake, sustained release, organ distribution, and transdermal or intestinal uptake that are problematic for the native drug. One of the most widely studied pro-drug forms of 5-FU is 5xe2x80x2-deoxy-5-fluorouridine (DFUR). DFUR is converted to 5-FU by pyrimidine nucleoside phosphorylase but has better cellular uptake properties than 5-FU. Like 5-FU, DFUR also releases FBAL as a toxic metabolite. Other nucleoside analogues of FUr include Tegafur [(1-(2-tetrahydrofuryl)-5-fluorouracil], Ftorafir [R,S-1-(tetrahydro-2-furanyl)-5-fluorouracil] and a variety of 5-fluorocytidine derivatives.
A variety of polymeric forms of 5-fluorouridine have also been prepared to provide sustained release of 5-FU. In U.S. Pat. Nos. 5,457,187; 5,614,505; 5,663,321, and 5,741,900, each of which is incorporated herein in its entirety, there are disclosed homo-oligomeric 5-fluorouridine and 5-fluorodeoxyuridine useful as a polymeric drug delivery system for production of FdUMP. Disclosed are methods of both preparing and utilizing these compositions. The oligomeric compounds were shown to traverse the cellular membranes of a variety of cell lines and were degraded to an active form. Homo-oligomeric FdUMP is taught to be a more effective cytotoxic agent in cell culture on a per residue basis than is monomeric 5-fluorodeoxyuridine. Homo-oligomeric FdUMP is taught to have the advantages of a longer residence time in-vivo and greater cytotoxicity per residue of 5-fluorodeoxyuridine and it is taught that oligomeric 5-fluorodeoxyuridine is therapeutically useful at lower doses than are monomeric 5-fluorouridine, 5-fluorodeoxyuridine, and 5-fluorouracil, making delivery of FdUMP as FdUMP[N] more cost effective on a per dose basis and less neurotoxic and cardiotoxic than delivery in a monomeric form. The reduced neuro- and cardiotoxicity is a consequence of lower levels of 2-fluoro-p-alanine (FBAL) released from the lower effective dosage.
The present invention relates to composition for treating neoplastic disease in animals including humans comprising a first composition comprising a TS inhibitor and a second composition comprising a nucleic acid-directed chemotherapeutic agent, and a method for treating neoplastic disease in animals including humans comprising administering to a host animal having a neoplastic disease a first composition comprising a TS inhibitor and a second composition comprising a nucleic acid-directed chemotherapeutic agent. In a preferred embodiment, the TS inhibitor is a homo-oligomer of FdUMP. By xe2x80x9cnucleic acid-directed chemotherapeutic agentxe2x80x9d is meant a composition that inhibits the synthesis, processing or function of RNA and/or DNA. In preferred embodiments, the nucleic acid-directed chemotherapeutic agent is a nucleoside analog that is incorporated into and affects subsequent processing and/or function of RNA and/or DNA. In a particularly preferred embodiment, the nucleic acid-directed chemotherapeutic agent is 5-FU or a pro-drug thereof.
In a further aspect, it has now unexpectedly been found that pharmaceutical compositions comprising 5-FU and homo-oligomeric FdUMP in accordance with the present invention demonstrate increased anti-proliferative activity and are more active than compositions containing only the individual components. In particular, significant anti-proliferative activity of the compositions of the present invention was found for concentrations of FdUMP[10] which alone had no significant effect on the growth of the cells.
In one aspect, the present invention relates to a composition having a synergistic anti-proliferative effect on neoplastic animal cells, comprising a synergistically effective amount of a homo-oligomer of FdUMP and 5-FU. In an embodiment, the animal cells are mammalian cells. In a further embodiment, the animal cells are human cells. In an embodiment, the neoplastic cell is a solid tumor cell, and in a further embodiment, the neoplastic cell is colorectal, breast, and ovarian cancer cells. In an embodiment, the homo-oligomer of FdUMP ranges from 2 to 26 monomers. In further embodiments, the homooligomer of FdUMP ranges from 5-15 monomers. In still further embodiments, the homooligomer of FdUMP ranges from about 8-12 monomers. In still further embodiments, the homooligomer of FdUMP ranges from about 9-11 monomers, and most preferably, contains 10 monomers.
In another aspect, the present invention relates to a method for the treatment of neoplastic disease in animals comprising administering to an animal having a disease a synergistically effective amount of a homo-oligomer of FdUMP and 5-FU.
In still a further aspect, the present invention relates to a method for inducing apoptosis in a tumor cell, comprising the step of administering to a cell culture or animal host having said tumor cell a composition comprising a synergistically effective amount of a homo-oligomer of FdUMP and 5-FU.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and together with the general description, serve to explain the principles of the invention.